Environmental factors drive latitudinal patterns of fine-root architectures of 96 xerophytic species in the dry valleys of Southwest China.

Fine-root architecture is critical feature reflecting root explorative and exploitative strategies for soil resources and soil space occupancy. Yet, studies on the variation of fine-root architecture across different species are scare and little work has been done to integrate the potential drivers on these variations along a biogeographical gradient in arid ecosystems. We measured root branching intensity, topological index, and root branching ratios as well as morphological traits (root diameter and length) in dry valley along a 1000 km latitudinal gradient.

Stockpiling turf alters microbial carbon and nitrogen use efficiency on the Tibetan Plateau.

Microbial carbon use efficiency (CUE) and nitrogen use efficiency (NUE) are crucial parameters reflecting soil C and N sequestration. Concerns about how artificial activities disturb alpine meadow ecosystem are increasing, but the knowledge of variances in microbial CUE and NUE in response to turf storage remains scarce. Here, we conducted a turf storage experiment on the Tibetan Plateau with two common storage methods, laying turfs method (LT) and stacking turfs method (ST).

Enzyme stoichiometry reveals microbial nitrogen limitation in stony soils.

Resource limitation for soil microorganisms is the crucial factor in nutrient cycling and vegetation development, which are especially important in arid climate. Given that rock fragments strongly impact hydrologic and geochemical processes in arid areas, we hypothesized that microbial resource (C and N) limitation will increase along the rock fragment content (RFC) gradient. We conducted a field experiment in Minjiang river arid valleys with four RFC content (0 %, 25 %, 50 %, and 75 %, V V) and four vegetation types (Artemisia vestita, Bauhinia brachycarpa, Sophora davidii, and the soil without plants).

A trade-off between leaf hydraulic efficiency and safety across three xerophytic species in response to increased rock fragment content.

Limited information is available on the variation of plant leaf hydraulic traits in relation to soil rock fragment content (RFC), particularly for xerophytes native to rocky mountain areas. In this study, we conducted a field experiment with four gradients of RFC (0, 25, 50 and 75% ν ν-1) on three different xerophytic species (Sophora davidii, Cotinus szechuanensis and Bauhinia brachycarpa). We measured predawn and midday leaf water potential (Ψleaf), leaf hydraulic conductance (Kleaf), Ψleaf induced 50% loss of Kleaf (P50), pressure-volume curve traits and leaf structure.

Age Determination and Growth Characteristics of the : A Comparison of Two Different Habitats in Western Sichuan Plateau, China.

This study proposes a rapid and non-destructive technique for determining the age of individuals in the field by observing the sequence of leaf scars. Based on two- to three-year-old seedlings, planted in a common garden in the western Sichuan Plateau, China, the study found that the rates of basal leaf production were consistent, with leaves growing from March to April and falling off from October to December, leaving behind basal leaf scars. Thus, the age of individuals in situ could be determined by counting the leaf scars.

Within leaf nitrogen allocation regulates the photosynthetic behavior of xerophytes in response to increased soil rock fragment content.

There is limited information on how plant functional traits vary with soil rock fragment content (RFC), especially for xerophytes growing in stony soils. We examined leaf functional traits of three xerophytes (Sophora davidii; Cotinus szechuanensi; and Artemisia vestita) grown under an RFC gradient in a heavy loamy soil. Our results show that photosynthetic capacity increased linearly with RFC in S.

Large-scale patterns of understory biomass and its allocation across China's forests.

Plant biomass storage and its allocation reflect the ecosystem productivity and adaptation to different environments. Understory vegetation is a significant component of any forest ecosystem and plays a vital role in biodiversity maintenance and the ecosystem's carbon cycle. Although many studies have addressed the relationships of climate, stand structure and resource availability with understory biomass and its allocation at local scales, the large-scale variation of understory biomass and allocation and their underlying mechanisms remain unclear.

Soil carbon, nitrogen and phosphorus ecological stoichiometry shifts with tree species in subalpine plantations.

Understanding ecological stoichiometric characteristics of soil nutrient elements, such as carbon (C), nitrogen (N) and phosphorus (P) is crucial to guide ecological restoration of plantations in ecologically vulnerable areas, such as alpine and subalpine regions. However, there has been only a few related studies, and thus whether and how different tree species would affect soil C:N:P ecological stoichiometry remains unclear. We compared soil C:N:P ecological stoichiometry of , and to primary shrubland in a subalpine region.

High nitrogen resorption efficiency of forest mosses.

Background And Aims: Nutrient resorption from senescing tissue is a key mechanism for plants to conserve nutrients, and can affect the nutrient dynamics of ecosystems. Yet, our limited knowledge of nitrogen (N) resorption and release from mosses hampers our understanding of the role of mosses as N sources and, thereby, N cycling in moss-dominated ecosystems. The aims of this study were to estimate N resorption efficiency (NRE) of two moss species, identify the pathways of N release from the mosses and to provide a better understanding of N cycling and budgeting strategies of mosses.

Linking leaf hydraulic properties, photosynthetic rates, and leaf lifespan in xerophytic species: a test of global hypotheses.

Premise Of The Study: Leaf venation and its hierarchal traits are crucial to the hydraulic and mechanical properties of leaves, reflecting plant life-history strategies. However, there is an extremely limited understanding of how variation in leaf hydraulics affects the leaf economic spectrum (LES) or whether venation correlates more strongly with hydraulic conductance or biomechanical support among hierarchal orders.

Methods: We examined correlations of leaf hydraulics, indicated by vein density, conduit diameter, and stomatal density with light-saturated photosynthetic rates, leaf lifespan (LLS), and leaf morpho-anatomical traits of 39 xerophytic species grown in a common garden.

Drivers of tree carbon storage in subtropical forests.

Tropical and subtropical forest ecosystems play an important role in the global carbon regulation. Despite increasing evidence for effects of biodiversity (species diversity, functional diversity and functional dominance), stand structural attributes, stand age and environmental conditions (climate and topography) on tree carbon storage, the relative importance of these drivers at large scale is poorly understood. It is also still unclear whether biodiversity effects on tree carbon storage work through niche complementarity (i.

Thinning-induced canopy opening exerted a specific effect on soil nematode community.

Changes in microclimate, soil physicochemical properties, understory vegetation cover, diversity, and composition as well as soil microbial community resulting from silvicultural practices are expected to alter soil food webs. Here, we investigated whether and how contrasting-sized canopy openings affect soil nematode community within a 30 year-aged spruce plantation. The results indicated that the responses of soil nematodes to canopy opening size were dependant on their feeding habit.

Comparisons of photosynthesis-related traits of 27 abundant or subordinate bryophyte species in a subalpine old-growth fir forest.

Bryophyte communities can exhibit similar structural and taxonomic diversity as vascular plant communities, just at a smaller scale. Whether the physiological diversity can be similarly diverse, and whether it can explain local abundance patterns is unknown, due to a lack of community-wide studies of physiological traits. This study re-analyzed data on photosynthesis-related traits (including the nitrogen, phosphorus and chlorophyll concentrations, photosynthetic capacities, and photosynthetic nutrient use efficiencies) of 27 bryophyte species in a subalpine old-growth fir forest on the eastern Tibetan Plateau.

Does thinning-induced gap size result in altered soil microbial community in pine plantation in eastern Tibetan Plateau?

Although the effects of gap formation resulting from thinning on microclimate, plant generation and understory plant community have been well documented, the impact of thinning on soil microbial community and related ecological functions of forests particularly in subalpine coniferous region is largely unknown. Here, the effects of thinning on soil microbial abundance and community structure using phospholipid fatty acid (PLFA) in pine plantations were investigated 6 years after thinning. The experimental treatments consisted of two distinct-sized gaps (30 m or 80 m in size) resulting from thinning, with closed canopy (free of thinning) as control.

The 'plant economic spectrum' in bryophytes, a comparative study in subalpine forest.

Premise Of The Study: Tradeoffs among functional traits of vascular plants are starting to be better understood, but it is unclear whether bryophytes possess similar tradeoffs or how trait relationships, or the 'economic spectrum', differ between the two groups.

Methods: We determined functional-trait values [including shoot mass per area (SMA), light-saturated assimilation rate (A), dark respiration rate (Rd), N and P concentrations (N and P), and photosynthetic N and P use efficiency (PNUE and PPUE)] and their bivariate relationships for 28 bryophytes growing in a subalpine old-growth fir forest on the eastern Tibetan Plateau. Trait values and scaling relationships of these bryophytes were compared with data for vascular plant leaves from the Global Plant Trait Network (GLOPNET) dataset.

Higher photosynthetic capacity and different functional trait scaling relationships in erect bryophytes compared with prostrate species.

Ecophysiological studies of bryophytes have generally been conducted at the shoot or canopy scale. However, their growth forms are diverse, and knowledge of whether bryophytes with different shoot structures have different functional trait levels and scaling relationships is limited. We collected 27 bryophyte species and categorised them into two groups based on their growth forms: erect and prostrate species.

The capsid protein p38 of turnip crinkle virus is associated with the suppression of cucumber mosaic virus in Arabidopsis thaliana co-infected with cucumber mosaic virus and turnip crinkle virus.

Infection of plants by multiple viruses is common in nature. Cucumber mosaic virus (CMV) and Turnip crinkle virus (TCV) belong to different families, but Arabidopsis thaliana and Nicotiana benthamiana are commonly shared hosts for both viruses. In this study, we found that TCV provides effective resistance to infection by CMV in Arabidopsis plants co-infected by both viruses, and this antagonistic effect is much weaker when the two viruses are inoculated into different leaves of the same plant.

Three new phenolic compounds from the leaves of Rosa sericea.

Two new flavonoids, quercetin-3-O-β-d-xylopyranosyl-(1→2)-α-d-ribopyranoside (1) and kaempferol-3-O-β-d-xylopyranosyl-(1→2)-α-d-ribopyranoside (2), and one new phenolic derivative, gallicin-p-O-(6'-O-caffeoyl)-β-d-glucoside (3), together with twelve known compounds were isolated from the leaves of Rosa sericea (Rosaceae family). The structures of the new compounds were established by means of spectroscopic analysis including one- and two-dimensional NMR spectroscopy. Some of the isolated compounds were tested for the cytotoxicity of a breast cancer cell (MCF-7) line.

[Short-term effects of low intensity thinning simulated by gap on ground microclimate and soil nutrients of pure spruce plantation].

Taking a dense spruce pure plantation as test object and simulating the formation of natural forest gap, this paper studied the effects of low intensity thinning by gap creation on the ground temperature, ground humidity, and nutrient contents in different soil layers of the plantation. In the first year of gap creation, the mean diurnal temperature in the gap across the growth season (May - September) increased, while the mean diurnal humidity decreased. The soil organic matter (SOM) and NH4(+) -N contents in O-horizon (humus layer) increased by 19.

[Effects of environmental stress on seedlings root growth and nodulation of leguminous shrubs in the dry valley of Minjiang River].

A field investigation was made to understand the seedlings root nodulation, biomass accumulation, root length, and fine root percentage of Sophora davidii, Indigofera lenticellata and Campylotropis polyantha along an altitudinal gradient on two contrasting sloped hills (north Zongqu and south Jingzhoushan) in the dry valley of Minjiang River. In the meantime, a greenhouse experiment was conducted to study the adaptation responses of 2 month-old S. davidii and C.

[Growth and reproduction of Rosa multibracteata population in Minjiang River dry valley].

Based on large area field survey and sampling plots investigation, this paper analyzed the distribution, growth and reproduction, and spatial differentiation of native Rosa multibracteata population in the dry valley of Minjiang River. The results showed that this shrub was widely distributed within the area about 170 km long and across the altitude between 1 200 m and 2 600 m from Mianchi Town of Wenchuan County to Zhenjiangguan of Songpan Town. The plant height, base diameter, age, canopy area, sprout number per clump, and hip number each cluster of the shrub were averagely (123.

[Effects of ramets adjustment on Quercus liaotungensis growth and seed generation].

This paper studied the effects of different ramets adjustment measures on the growth and seed generation of Quercus liaotungensis shrub in the upper reach of Minjiang River. The results showed that artificially adjusting ramets number largely affected the growth of plant height and sexual reproduction of Q. liaotungensis.